World Bank Technical Paper No. 389. By the International Commission on Irrigation and Drainage. This paper is the revised edition of Technical Paper No. 99, written in 1989. It provides the basis for the preparation of manuals necessary for managers and staffs to perform needed activities at the proper time. The guide provides a comprehensive list of issues that should be addressed in operation and maintenance manuals for irrigation and drainage systems, and a listing of published materials and working papers which will assist in the formulation of plans for operation and maintenance. The paper serves as a valuable tool to help improve the performance of irrigation and drainage systems and to assist managers in developing and improving effective organizations to serve water consumers better.